Bottom closing apparatus for closing the bottom flaps of paper bags and the like

ABSTRACT

Apparatus for folding the trailing bottom flap of a paper bag over the bottom of the bag into a closed position in cooperation with a power driven bag forming drum of a paper bag making machine having a bag blank releasably clamped thereto. The bottom closing apparatus includes a series of coaxial and circumferentially spaced bottom closing discs rotatably mounted in radially outwardly spaced relation with respect to the periphery of the bag forming drum, to rotatably move in the same direction about axes spaced radially of the surface of the drum into interdigitating relation with respect to each other. The bottom closing discs each travel at a higher rate of speed than the speed of rotation of the drum and have flap closing fingers extending closely adjacent the periphery of the drum to accommodate a first set of fingers to get behind and lift the trailing bottom flap of the bag into an upward position to accommodate the second series of fingers to overtake the bottom flap when in a straight upward position and fold it downwardly over the previously folded trailing bottom flap of the bag into a closed position.

United States Patent 1,567,437 12/1925 Hartman Inventor Herbert H. WeberSheboygan, Wis.

Appl. No. 755,674

Filed Aug. 27, 1968 Patented Feb. 23, 1971 Assignee H. G. Weber andCompany, Inc.

Kiel, Wis.

References Cited UNITED STATES PATENTS Primary Examiner-Bernard StickneyAttorney-Hill, Sherman, Meroni, Gross and Simpson ABSTRACT: Apparatusfor folding the trailing bottom flap of a paper bag over the bottom ofthe bag into a closed position in cooperation with a power driven bagforming drum of a paper bag making machine having a bag blank releasablyclamped thereto. The bottom closing apparatus includes a series ofcoaxial and circumferentially spaced bottom closing disks rotatablymounted in radially outwardly spaced relation with respect to theperiphery of the bag forming drum, to rotatably move in the samedirection about axes spaced radially of the surface of the drum intointerdigitating relation with respect to each other. The bottom closingdisks each travel at a higher rate of speed than the speed of rotationof the drum and have flap closing fingers extending closely adjacent theperiphery of the drum to accommodate a first set of fingers to getbehind and lift the trailing bottom flap of the bag into an upwardposition to accommodate the second series of fingers to overtake thebottom flap when in a straight upward position and fold it downwardlyover the previously folded trailing bottom flap of the bag into a closedposition.

PATENTEU FEB23 1971 SHEEI 1 OF 2 R. w m v W AT'TORNE YS BOTTOM CLOSINGAPPARATUS FOR CLOSING THE BOTTOM FLAPS OF PAPER BAGS AND THE LIKESUMMARY AND OBJECTS OF THE INVENTION A bottom flap closing apparatus forpaper bags and the like arranged to handle a far wider range of lengthsof flaps than has heretofore been considered possible, by the use of twoseries of circumferentially spaced bag closing discs spaced radially ofthe periphery of the bag forming drum and driven in the same directionat a higher rate of speed than the speed of travel of the bag formingdrum, to more efficiently get behind and pick up the flap and then movethe flap from its trailing position to a straight up position and thendownwardly over the bottom of the bag into a closed position.

A principal object of the present invention, therefore, is to provide asimplified and more efficient apparatus for closing the bottom flaps ofpaper bags and the like in cooperation with the bag fonning drum of abag marking machine, and arranged with a view toward more efficientlyclosing a wider range of lengths of bottom flaps of paper bags than withformer bag closing methods and apparatus.

Another object of the invention is to simplify the bottom flap closingoperations of paper bags on bag making machines by providing two seriesof bag closing discs cooperating with a power driven bag forming drum,and spaced radially therefrom and moving into interdigitating relationwith respect to each other at the same rates of speed, and at a rate ofspeed as the speed of travel of the drum, to move a first set of discsto get behind and pick up the bottom flap of the bag and move the flapinto a generally upright position, to then be overtaken by a secondseries of discs in advance of the first series and moved downwardly intoa closed position.

These and other objects of the invention will appear from time to timeas the following specification proceeds and with reference to theaccompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic view in sideelevation diagrammatically showing a portion of the bag forming drum ofa bag making machine with the bottom flap closing discs in cooperationtherewith adjacent the stripping station of the machine.

FIG. 2 is a partial fragmentary horizontal sectional view taken througha second series of bottom flap closing discs and fragmentarily showingthe first series of discs interdigitating relation with respect thereto.

In the diagrammatic illustration of the invention of FIG. 1 of thedrawings, I have diagrammatically shown a portion of a bag forming drumof a typical bag forming machine and have shown a bag 11 being strippedfrom the drum'10 and having a trailing bottom flap l2 folded over thebottom of the bag over a previously folded trailing flap (not shown). Ihave also shown the positions of the bottom flap 12 when being foldedfrom its trailing to its closed position, overlapping the bottom of thebag. The forming drum 10 is mounted for rotation about a horizontal axisand is driven at a predetermined rate of speed to carry a bag to be cutoff, scored, formed, glued and to fold the trailing and glued bottomflap of the bag backwardly along the bottom previously folded leadingflap of the bag, to be sealed thereto. During the cutoff, scoring,forming and gluing operations, the bag blank is clamped to the drum byreleasable circumferentially spaced leading and trailing clamps at eachstation of the drum, releasing the formed bag as stripped from the drum.These clamps may be of any conventional form commonly used on bag makingmachines and are no part of the present invention so need not be shownor described in detail.

A first series of spaced bottom flap closing discs 13 is shown in FIGS.1 and 2, as being mounted in side by side relation on a transverse shaft15, spaced radially of the periphery of the drum 10 and rotatably drivento drive the discs 13 at a higher peripheral speed than the speed ofrotation of the drum 10 and in an opposite direction than the directionof rotation of said drum, but in the same direction as the direction oftravel of said drum.

A second series of bottom closing discs 16 is shown as being mounted ona transverse shaft 17 spaced circumferentially of the shaft 15 andradially of the periphery of the drum I0 and rotatably driven in thesame direction and at the same rate of speed as the shaft 17.

In advance of the bottom closing discs 16 is a plurality of strippers 19having stripper plates 20 extending into grooves 21 formed in thesurface of the drum 10 and conforming generally to the peripheries ofthe discs 16, to strip the bag from the surface of the drum 10 with thebottom flap 12 in a closed position. The bottom fiap 12 is held in aclosed position by the peripheries of the second series of bottomclosing discs 16 and is retained in a closed position as stripped fromthe drum 10. As stripped from the drum 10, the bag is advanced along thestripper plates 20, over idlers 22 disposed between said stripper platesand under a series of laterally spaced transfer belts 23. The belts 23turn about direction changing idlers 24 disposed between the bottom flapclosing discs 16. The belts 23 cooperate with a series of similartransfer belts 25 turning about direction changing idlers 26 adjacentthe discharge ends of the stripper plates 20, to form a traveling nipalong which the bag is conveyed with its bottom flap in a closedposition. The belts 25 may be driven at the peripheral speed of the bagclosing drum 10 while the belts 23 may be driven at a slightly higherrate of speed, to effect an overtravel of the bottom flap of the bag, tomaintain the bottom flap in its closed position.

In FIG. 2 I have shown a generally horizontal sectional view takenthrough the second series of bottom closing discs 16 and have shownthese discs mounted on the transverse drive shaft 17. Each disc 16 has ahub 27, shown in FIG. 2 as being split, in which the split portion ofthe hub is drilled to accommodate clamping of the hub to the shaft 17 tobe driven therefrom. A key or pin (not shown) may be provided for eachdisc to maintain the disc in position on the shaft. The shaft 17 isjournaled in side frame members 30,30 of a frame 31 of the bag makingmachine on antifriction bearings 33,33 and extends beyond one side framemember 30 and has a spur gear 35 keyed or otherwise secured to theprojecting end thereof. The spur gear 35 is shown as driven by a spurgear 36, which may be driven by the bag forming a drum 10 through asuitable gear train (not shown) in any well known manner, to effect adrive to the bottom closing discs 16 at a higher rate of speed than thespeed of travel of the bag forming drum 10, to accommodate the discs 16to get behind the bottom flap 12 of the bag as raised by the discs 13,and to fold the flap over the traveling bag into its closed position asit is stripped from the drum 10 (FIG. 1). v

Journaled on the shaft 17 inwardly of the side plates 30 and spacedoutwardly of each side of the outer end bottom closing discs 16 is atransfer cylinder 37 clamped to a drive sleeve 39 journaled on the shaft17 on bearings 40. The transfer cylinders 37 are rotatably driven at thesame peripheral speed as the peripheral speed of the drum 10 and engagethe opposite side edges of the bag on the idlers 22 and convey the bagalong the stripper plates 20 and into the space between the transferbelts 23 and 25. The transfer cylinders 37 have webs 41 partially cutaway to counterbalance the offcenter weights of the bottom closing discs16 and have pressure pads 43 extending inwardly therefrom exertingpressure on the leading corners of the bottom of the bag, to maintainthe leading flap of the bottom in its closed or tucked position as thetrailing bottom flap 12 is folded over the previously folded trailingflap by the bottom closing discs 16.

As shown in FIG. 2 a gear train 44, driven from a spur gear 45 keyed orotherwise secured to the shaft 17, is provided to drive the associatedtransfer cylinder at the peripheral speed of the bag forming drum 10.

The shaft 15 of the first series of bottom flap closing discs 13 isjournaled in the side frame members 30 of the frame 31 of the bag makingmachine, and is driven from the bag forming drum, to rotatably drive thebottom flap closing discs 13 in the same direction and at the same rateof speed as the bottom flap closing discs 16. The bearing support anddrive for the shaft 15 is the same as that for the shaft 17 and thebottom flap closing discs 13 are mounted on the shaft 15 in the samemanner the discs 16 are mounted on the shaft 17, so a detaileddescription thereof need not be repeated. The shaft 15, however, doesnot have bag transfer cylinders mounted thereon on the outer sides ofthe bottom flap closing discs 13, since the bag is not transferred bythe strippers 20 until the back flap is folded down over the bag by thebottom flap closing discs 16.

Referring now in particular to the forms of discs 13 and 16, as shown inFIG. 1, the discs 13 and 16 of each series of discs are of the sameconstruction and are positioned on their respective shafts in the samephase relation with respect to each other. The discs 13 are angularlypositioned on the shaft 15 to first get behind the trailing end of thebottom flap and to raise the flap, to be picked up by the discs 16 whenthe flap is in an upright position. Each disc 13 has a chordal surface47 forming a pick up finger of sufficient length to pick up a trailingbottom flap of the bag and to raise the flap in position to be picked upby a corresponding chordal surface or pick up finger 48 of aninterleaving disc 16.

The pickup finger 47 terminates at its outer end, adjacent the peripheryof the disc into a circumferential peripheral surface 49 formed on anarc struck from the axis of rotation of the shaft 15, and shown asextending for a greater portion of the periphery of the bottom flapclosing disc 13. The peripheral surface converges from thecircumferential surface 49 into a receding peripheral surface 50converging toward the shaft 15 as it extends to the chordal surface orpickup finger. The spacing between the circumferential surface 49 of thedisc 13 and the periphery of the drum is sufficient to accommodate thebag with its trailing bottom flap to extend thereunder and toaccommodate the pick up finger to hinge or fold the flap into an uprightposition, to be picked up by the pick up finger 48 of the bottom flapclosing disc 16.

The chordal surface or finger 48 of the bottom closing disc 16terminates into a circumferential surface 51 struck from an arc coaxialwith the axis of rotation of the shaft 17 and of the same radius as theradius of the arc of the circumferential peripheral surface 49 of thebottom flap closing disc 13. The circumferential surface 51 serves tomaintain the bottom flap in the closed position shown in FIG. 1 as itpasses along the stripper plates 20 and over the rollers 22 and to holdthe flap in this position as it passes under the transfer belts 23.

In FIG. 1 the bottom flap closing discs 13 are shown in solid in thepositions they will assume when the bottom flap of the bag is in anupright position, in position to be picked up by the fingers 48 of thebottom flap closing discs 16. The discs 16 are shown by solid lines asangularly positioned in trailing relation with respect to discs 13 totake over the bottom flap closing operation as the bottom flap is movedinto the upright position l2fshown in FIG. 1.

In picking up the bottom flap the finger 47 is shown in a broken lineposition 47a moving into position to overtake the bottom flap inposition 12a and get behind said bottom flap and then raise the bottomflap through positions 12b, 12c, 12d, 12c and 12f and to continue thehinging of the bottom flap until it can be picked up by the finger 48and moved into a closed position through positions 12g, 12h, 12i, 12j,12k and 12! to then be engaged by the circumferential peripheralsurfaces 51 of the bottom flap closing discs 16 and retained thereby inits closed position, as the bag is transferred along a stripper surface20 of the stripper 19 under the transfer belts 23 and over the transferbelts 25 into the nip between said belts.

It may be seen from the foregoing that a first and second series ofbottom flap closing discs 13 and 16 rotatably driven in interdigitatingrelation with respect to each other at higher rates of speed than thespeed of travel of the bag forming drum l0 rotate in such relation withrespect to the bag forming drum that the first series of discs willfirst overtake the trailing bottom flap 12a of the bag 11 travelingalong said bag forming drum and then hinge the flap upwardly as it istraveling along the drum and that as the bottom flap is in an uprightposition 12f, the second series of bottom flap closing discs 16 willengage and fold the bottom flap over its previously folded leading flapinto its closed position to be carried away and sealed into its closedposition While I have herein shown and described one form in which theinvention may be embodied, it may readily be understood that variousvariations and modifications in the invention may be attained withoutdeparting from the spirit and scope of the novel concepts thereof.

I claim:

1. In a bag making machine and in combination with power driven bagforming means having a traveling surface carrying paper bag blanks andprogressively forming the blanks into paper bags and closing and sealingthe bottom flaps thereof,

a first bottom flap closing disc, a second bottom flap closing discspaced in advance of said first bottom flap closing disc, said first andsecond bottom flap closing discs moving in interdigitating relation withrespect to each other at higher rates of speed than the speed of travelof said drum, means mounting said first and second bottom flap closingdiscs in spaced relation with respect to the traveling surface of saidbag forming means and in spaced relations with respect to each other, tospace said second flap closing discs ahead of said first flap closingdiscs, said discs each having a pick up finger extending to a positionadjacent the periphery of said traveling surface and driven to travel inthe same general direction as the direction of travel of said travelingsurface and at a higher rate of speed than the speed of travel of saidtraveling surface, whereby a first disc may overtake and get behind abag bottom flap on said traveling surface and move the flap into agenerally upright position and a second of said discs may overtake theflap when in an upright position and fold the flap downwardly along thetraveling bag into a closed position, 2. A bag making machine inaccordance with claim 1, wherein the means mounting said discs in spacedrelation with respect to said traveling surface and in spaced relationwith respect to each other comprises parallel spaced shafts extendingtransversely of said drum and parallel to the surface of said drum, andwherein drive means are provided for driving said shafts and discs athigher rates of speed than the speed of travel of said travelingsurface. 3. A bag making machine in accordance with claim 2, whereinplurality of discs are provided on each shaft, and wherein said discs onsaid spaced shafts are mounted in interleaving relation with respect toeach other and are rotatably driven by said shafts to move in the samedirection of rotation in interdigitating relation with respect to eachother. 4. A bag making machine in accordance with claim 2, wherein eachbottom flap closing disc has a circumferential peripheral portionextending for a portion of the periphery thereof and spaced from thesurface of said traveling surface and has a finger extending chordallyof said circumferential surface and inwardly therefrom, and wherein thefingers of said first and second discs are angularly spaced with respectto each other to accommodate a first finger to overtake and move behindthe trailing end of a bottom flap and raise it into an upright positionto then accommodate the finger of a second disc in cooperation with theperipheral portion thereof to fold the bottom flap downwardly along thebottom of the bag and to retain the flap in this position to beadhesively secured thereto. 5. A bag making machine in accordance withclaim 2,

wherein a plurality of aligned discs are provided on each shaft to movein interdigitating relation with respect to each other,

and each have a circumferential peripheral portion struck from the axisof rotation of the respective shaft and extending for a portion of theperiphery thereof and spaced from the periphery of the traveling surfaceto accommodate a bag to pass in the space therebetween,

wherein said circumferential periphery terminates at one end thereofinto advance flap folding finger extending generally chordally of thecircumferential peripheral por tion thereof, and

wherein the discs on the second shaft are spaced angularly with respectto the discs on the first shaft, to come into folding cooperation withthe bottom flap of the bag as said flap is moved to a generally uprightposition by said first bottom flap closing discs and to hinge the flapdownwardly along the bottom of the bag in cooperation of the peripheralportions thereof.

6. A bag making machine in accordance with claim 4,

6 wherein the traveling surface is a bag forming drum, wherein astripper underlies said discs on said second shaft conforms generally tothe peripheral surface thereof to complete the back flap closingoperation as the bag is stripped from said bag forming drum and whereinspaced transfer belts having a space therebetween extend in advance ofsaid stripper for transferring the bag with the back flap in closedrelation for further operations.

7. A bag making machine in accordance with claim 6, wherein a pluralityof aligned interleaving bottom flap closing discs are mounted on eachshaft and'a re rotatably driven thereby into interdigitating relationwith respect to each other.

8. A bag making machine in accordance with claim 7, wherein transfercylinders are mounted on said second shaft adjacent opposite endsthereof, and

wherein drive means are provided for said transfer cylinder to drivesaid transfer cylinders at the speed of travel of said bag forming drumand progress the bag along said stripper into the nip between saidtransfer belts.

UNITED. STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,564,979 Dated February 23, 1971 Inventor(s) HERBERT H. WEBER It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 1, line 20, change "marking" to --making--;

line 47, before "interdigitating", insert --in--.

Column 4, line 27, change "relations" to -reiationline 53, after"wherein", insert --a--.

Column 6, line 2, before "conforms", insert --and-- Signed and sealedthis 21 st day of March 1972.

(SEAL) Attest:

EDWARD M.F'LETGHER,JR. ROBERT GO'ITSCHALK Attesting Officer Commissionerof Pat

1. In a bag making machine and in combination with power driven bagforming means having a traveling surface carrying paper bag blanks andprogressively forming the blanks into paper bags and closing and sealingthe bottom flaps thereof, a first bottom flap closing disc, a secondbottom flap closing disc spaced in advance of said first bottom flapclosing disc, said first and second bottom flap closing discs moving ininterdigitating relation with respect to each other at higher rates ofspeed than the speed of travel of said drum, means mounting said firstand second bottom flap closing discs in spaced relation with respect tothe traveling surface of said bag forming means and in spaced relationswith respect to each other, to space said second flap closing discsahead of said first flap closing discs, said discs each having a pick upfinger extending to a position adjacent the periphery of said travelingsurface and driven to travel in the same general direction as thedirectioN of travel of said traveling surface and at a higher rate ofspeed than the speed of travel of said traveling surface, whereby afirst disc may overtake and get behind a bag bottom flap on saidtraveling surface and move the flap into a generally upright positionand a second of said discs may overtake the flap when in an uprightposition and fold the flap downwardly along the traveling bag into aclosed position.
 2. A bag making machine in accordance with claim 1,wherein the means mounting said discs in spaced relation with respect tosaid traveling surface and in spaced relation with respect to each othercomprises parallel spaced shafts extending transversely of said drum andparallel to the surface of said drum, and wherein drive means areprovided for driving said shafts and discs at higher rates of speed thanthe speed of travel of said traveling surface.
 3. A bag making machinein accordance with claim 2, wherein plurality of discs are provided oneach shaft, and wherein said discs on said spaced shafts are mounted ininterleaving relation with respect to each other and are rotatablydriven by said shafts to move in the same direction of rotation ininterdigitating relation with respect to each other.
 4. A bag makingmachine in accordance with claim 2, wherein each bottom flap closingdisc has a circumferential peripheral portion extending for a portion ofthe periphery thereof and spaced from the surface of said travelingsurface and has a finger extending chordally of said circumferentialsurface and inwardly therefrom, and wherein the fingers of said firstand second discs are angularly spaced with respect to each other toaccommodate a first finger to overtake and move behind the trailing endof a bottom flap and raise it into an upright position to thenaccommodate the finger of a second disc in cooperation with theperipheral portion thereof to fold the bottom flap downwardly along thebottom of the bag and to retain the flap in this position to beadhesively secured thereto.
 5. A bag making machine in accordance withclaim 2, wherein a plurality of aligned discs are provided on each shaftto move in interdigitating relation with respect to each other, and eachhave a circumferential peripheral portion struck from the axis ofrotation of the respective shaft and extending for a portion of theperiphery thereof and spaced from the periphery of the traveling surfaceto accommodate a bag to pass in the space therebetween, wherein saidcircumferential periphery terminates at one end thereof into advanceflap folding finger extending generally chordally of the circumferentialperipheral portion thereof, and wherein the discs on the second shaftare spaced angularly with respect to the discs on the first shaft, tocome into folding cooperation with the bottom flap of the bag as saidflap is moved to a generally upright position by said first bottom flapclosing discs and to hinge the flap downwardly along the bottom of thebag in cooperation of the peripheral portions thereof.
 6. A bag makingmachine in accordance with claim 4, wherein the traveling surface is abag forming drum, wherein a stripper underlies said discs on said secondshaft conforms generally to the peripheral surface thereof to completethe back flap closing operation as the bag is stripped from said bagforming drum, and wherein spaced transfer belts having a spacetherebetween extend in advance of said stripper for transferring the bagwith the back flap in closed relation for further operations.
 7. A bagmaking machine in accordance with claim 6, wherein a plurality ofaligned interleaving bottom flap closing discs are mounted on each shaftand are rotatably driven thereby into interdigitating relation withrespect to each other.
 8. A bag making machine in accordance with claim7, wherein transfer cylinders are mounted on said second shaft adjacentopposite ends thereof, and wherein drive means are provided for sAidtransfer cylinders to drive said transfer cylinders at the speed oftravel of said bag forming drum and progress the bag along said stripperinto the nip between said transfer belts.